如何分离Typescript中的数组

Question

我正在用Angular2创建一个应用程序，并且我有一组派对。

const PARTIES: Party[] = [ 
    { id: 1, title: "Main Event", description: "The biggest, most extravagant event in the last 10,000,000 years." }, 
    { id: 2, title: "Secondary Event", description: "The not as biggest, less extravagant event in the last 10,000,000 years." }, 
    { id: 3, title: "Another Event", description: "N/A" }, 
    { id: 4, title: "Another Event", description: "N/A" }, 
    { id: 5, title: "Another Event", description: "N/A" }, 
    { id: 6, title: "Another Event", description: "N/A" }, 
    { id: 7, title: "Another Event", description: "N/A" }, 
    { id: 8, title: "Another Event", description: "N/A" }, 
    { id: 9, title: "Another Event", description: "N/A" }, 
    { id: 10, title: "Another Event", description: "N/A" } 
]; 

同时保留原始阵列，我想起来拆分此阵列分成的3

段在普通的旧的JavaScript，我会使用以下内容。

var chunk_size = 3; 
var arr = PARTIES; 
var groups = arr.map(function(e,i){ 
    return i%chunk_size===0 ? arr.slice(i,i+chunk_size) : null; 
}) 
.filter(function(e){ return e; }); 
PARTIES = groups 

但是，我正在使用TypeScript。是否有任何可能的方式来执行我想用TypeScript实现的目标？

Answer 1

你的JavaScript代码：

var chunk_size = 3; 
var arr = PARTIES; 
var groups = arr.map(function(e,i){ 
    return i%chunk_size===0 ? arr.slice(i,i+chunk_size) : null; 
}) 
.filter(function(e){ return e; }); 
PARTIES = groups 

是不正确的。如果是这将是有效的打字稿和它只是工作，因为JavaScript是打字稿https://basarat.gitbooks.io/typescript/content/docs/why-typescript.html :)

修复

以下是工作示例：

const PARTIES = [ 
    { id: 1, title: "Main Event", description: "The biggest, most extravagant event in the last 10,000,000 years." }, 
    { id: 2, title: "Secondary Event", description: "The not as biggest, less extravagant event in the last 10,000,000 years." }, 
    { id: 3, title: "Another Event", description: "N/A" }, 
    { id: 4, title: "Another Event", description: "N/A" }, 
    { id: 5, title: "Another Event", description: "N/A" }, 
    { id: 6, title: "Another Event", description: "N/A" }, 
    { id: 7, title: "Another Event", description: "N/A" }, 
    { id: 8, title: "Another Event", description: "N/A" }, 
    { id: 9, title: "Another Event", description: "N/A" }, 
    { id: 10, title: "Another Event", description: "N/A" } 
]; 

var chunk_size = 3; 
const groups = PARTIES.map(function(e,i){ 
    return i%chunk_size===0 ? PARTIES.slice(i,i+chunk_size) : null; 
}) 
.filter(x=>!!x) 

console.log(groups); 

的一些注意事项的修复：

• const不能被重新分配。所以你不能重新分配给各方
• 各方的类型（[]）是不一样的类型groups（[][]），所以你不想来指派反正
• 不如在filter使用真实boolean代替truthy/falsy检查。更多：https://basarat.gitbooks.io/typescript/content/docs/tips/truthy.html